Telephone-exchange system.



No. 854,279. PATENTED MAY 21, 1907. w. w. DEAN.

I TELEPHONE E XGHANGE SYSTEM.

APPLIOATION nun In 19. 1905.

2 8HEETBSHBET 1.

No. 854,279. PATENTED MAY 21, 1907.

W. W. DEAN. TELEPHONE EXCHANGE SYSTEM.-

APPLICATION FILED MAY 19. 1905.

; ,sT 'rEs w. DEAN, or H1 COMPANY, OF ELYRI PATENT OFFICE;

TELEPHONE-EXCHANGE SYSTEM.

'Noi854,279.

fipocification ofllettera Patent.

Patented Kay 21, 1907.

Kay 19, 1905'. I. 861,131.

To all whom it may conccrn:,

Be it known that I, WILLIAM W. DEAN, a citizen of the United States, residnig at Ely ria, in the county of Lorain and State of Ohio, have invented certain new and useful Improvements in TeleRhone-Elrchange Systems, of which the to owing is a specification. reference being had therein to the -ac companying drawings.

My inventionrelates to telephone exchange systems, and has for its object the arrangementof a system so that the subscriber may at all times absolutely control his line, and the lines cannot be "hung up the most improved with automatic signals, considerable anno ance and delay have been caused by the failure of operators to disconnect line's instantaneously upon receiving the disconnect signal.

In a system having double supervisory lam s, the operator may of course be called by either subscriber flashing his lamp. In the case of the subscriber who was the caller before. this usually means that lie-wants a recall.? and the same operator willnaturally make the second connection, so 'that 'in any case he would have to wait until this operator was at leisure to attend'to call. Not-so the called subscriber, Unless-he should chance to come same answering multiple jack only would be thenreached and in use; and it would be contrary to the rulesof all well regulated 'exch to 'rmita call coming in on a multiple jack to be completed by the subscriber's operator who had previously connected that jack for acall. Such a course would inevitably lead to confusion through a lack of control by the manager, of the distribution of the lines for answeringpurposes among the subscribers operators. It being ilnppssible for the re viously called subscriber to do more t an idly flash his supervisory, his line is hung up however. in on the 1n.a double sense, for he is forced to waitfor disconnection upon the convenience of the other man's operator. and he cannot reach lus own operator to get relief.

v my present invention the-foregoing difliculties and man others are obviated,

withoutin any way changing or by the opera-1 tors through failure to disconnect promptly systems equipped this new position as his caller,

the efliciency of the present standard common battery circuits. g

. Briefly stated, my invention comprises supplementary cut-ofi relays inserted in the cord circuits and controlling the continuity thereof between the plugs and the ordinary supervisories. These relays are brought into service at the end of a communication when the subscribers hang up their receivers, their circuits closed (and being locked),

when the supervisories have finally responded, so that the plugs are discomiected from the-intermediate cord circuit apparatus, and each subscriber's line is immediately free, the cut-off relays at once putting them back on their line signals, so that they can make calls and be answeredin the ordinary way without regard to'the idle and disconnected plugs sticking in their jacks. My invention is illustrated in the accompanying awings, wherein lgure l is a diagram showing a central office connecting circuit equipped with my invention, and a subscriber's line circuit ada ted to cooperate therewith; Fig. 2 isg. ed cord-circuit; and Fig. 3 illustrates the adaptability circuit. Figs. 1 and 3 are meant to be read together in order to get the proper sequences of operation.

Referringto the drawings, A in'Fig. 1 and A in Fig. 3 are two subscribers stations,

I having the same apparatus throughout, and

the same line connections, so the description of 1 will sufiice for both.

' R is the receiver connected in the bridge wire of a Wheatstone brid e having choke coils in two of its arms tint balancing noninductive resistance in the other two, the idea that battery currents do not affect the lreceiver, but voice currents are forced through it.

of the invention to a trunk T is the transmitter, H is the switch-hook,

Q is the ringer ,and C the condenser, all these being of the usual type. From the substa tion' the line wires 1 and 2 pass to the central oflice to the contacts n and 11 of the cutoff relay N connected B. e line relay when energized by closure of the circuit at the sub-station, lights the through its whole length from ground to the sleeve side of jack, and normally deenergized. Contact 1l' is grounded at 3 and contact I: is connectedby wire 4' throu h the line relay M to the main battery lamp m through the wire 5. The line jack is shown at J, with sleeve and spring contacts j, j, and with this jack coeperates the an-j swering plug P. lt will be understood that although I-have only shown one jack for each line, there are supposed to be multiple jacks where required. I

The plug P and the plug P are normally connected by way of the conductors 6'8 10-12 and 79l113, broken of course by the condensers C, C. Between 6 and 8, 10 and i2, 7 and 9, and 11 and 13 are inserted contactsvcontrolled in pairs by the relay the corresponding relays S, S forming .a

similar bridge on the other side. When a plug is inserted the relay S or S pulls up at once, taking current from ground to battery and ground over the sleeve side, 97'2, in

series with the cut-ofi relay N. This puts battery on the wire 32 or 33, as the case may be, and the lamp 3 or s is thereafter con- I trolled by the relay S or S itself controlled a overthe tip side of line from the subscribers .-station; r g .1.- i rom'extra back contacts in series, of the armatures of relays S? and 3, this oil-suites j relays S and S l derive thecircuitof my cont-cl relays, D, D, which may be fiaced as 'iollows: battery B, 23, L35, 34,17,,;i6,;$i}3

15, n, 14,30 and ground.- Besides the;

controlled by the lockingfirelay E. Q the relays D, D must e-normally deenere] 1 gized, and in order that they may cut or the 1 his receiver, whereupon; this relay plugs, two steps 5 should The required;

' 'l the called subscriber should have answerscl;

whereupon the relay holdup, end-Z second the subscribershould have s o a have let go; i put in the relayli in order to respond to these two conditionsltis error-t; gisedthroughthe 34% by the relaiylil when the called subscriheranswers, battery i 'then coming on. the 'relay which pullaup uts hatteryqon retires lock, hythe cir of the answering and 35 cuit have In 1323?; tha t it sha 1m g 0t t t *3 mu tin their seats, each seat provided with the plug-seat switch closed to ground the wire 24 and relay Fthrough the branches 26-28, and 2527 when the plugs are out.

The object of the-modified arrangement in 2 is to make the I independent. This is accomplished by havirig locking windings on the relays D and D, each winding controlled by a contact of its nnect mechanigfi i 1- sides of the cord own relay,- and a contact in its own plug-seat switch. These two relays are primarily opdescribed in connection with 1.;- As soon as they are operated they look by connecting the battery wires21 and 22 to the locking d, arid thence through their respec tive ground wires 25 and 26 ,to the plug-seat switches 27 and 28. [The locking relay F, in this case has its circuit 37. controlled by 'auxiliary contacts of relay D'. 2 Referring now to Fi .3, I have here-shown the incoming trunk plug P3 are connected for purposes of conversation by conductors 3H1, ML-42. interposed in the trunk is the repeating coil ,1, 'i, '8' i .11 between equal windings on each side of the coil, a condenser being interposed to prevent trunk line is normally broken at contacts of relay S which corresponds to the super- .visory relay S in the cord-circuit. In series with the 'i, 1?, of the repeating coil,

visory relay-,3 inthe);cord-circuit and; the relay D is co ntrolled bythetwo' relays D Th pore o d-of he circuiFshowii in-Fig, l 0 te bscfilier. A 'calls, closing hook contacts rent and lamp m'li" Plug is inserted and number obtained; ,The'lindwahted is inserted the cut-ofl circuit completed through the sleeve sideof they cord as fol- RelayS pulls up and'puts battery "on wire traced; and as relay N has pulled up, current continues through armature 1n and by the-iollo path-2,1 T, l, j, p, ti, ros 31 Relay" 3 pulls up, extinguishes lamp 8, and breaks thecircuit of relays D, F and B. When the called subscriber answers relay S pulls up, extinguishes lamp 3' and puts battery on relay F by the following path: 31, B.- 23, i8, 34, F. 24, 2c, 28 0 25, 2?. Relay F pulls u and locks itself by closing f on to 35. This a so puts battery on to the wire 34: through 35, so that when the two annatures of relays S and S ultimately fallback when the passage of battery current. .The con-' neotion 39-on the tip side of the incoming and s wither-rememseries, batterybeihg Lillie "relay takes cur-.

lows: 3l,B. 23', S', '21,; 7,32, 2, l l, ground.

erated by their upper windings, d, as already a trunk line suppose to interconnect two exchanges; The outgoing'trunk jackJ and is a shunt relay-5D, connected around the out lamp X and also controls the continuity 95 f Jlhe relay Dcorresponds to the super:

mop"

ipp i d h lh g n i hy t looming relay si mer ilfFigs'. i and v 1The "nt'and functioning of my hette'r' understood h'om a ",sta e it q operationxthau from fur-- 'ther.'detailed;deseription tested and plug 1?":i nserted; When plug 1? being closed at sub-sta -tron,fcurrent flows over the pathralready both; subscribers have hung up their re- .ceivers,; (owing to the then breakingtof the line circuit,) the following circuits for relays D, D, will be established: .3L,B, 23, f.

,which areharmless niay be left inthe jacks without affecting thelines in any way; and in order to keep current on the wires 32, 33 so as to continue the lighting of lamps s, s,

when once they glow, I provide the grounds .29 and 30 which are put on by the respective relays D, D to replace the grounds of the cut-off relays, which of course are removed from the sleeve side of the cord when the latter is broken.

The cord thus being disconnected from the lines, two results are achieved: First. the

subscribers who were connected are instantly free to make other calls, because their cutoff relays X put their lines back on to their line relays. Second, neither line tests busy. This is a very important point, for as the percentage of busy lines in a busy exchange ranges from 10 to 17 per cent. it is safe to assumethat the operator with 16 or 17 pairs of cords to attend to is responsible for a suflicient part of this percentage to make a substantial gain by my invention. According to the old system, as long as a plug is in the jack the line tests busy.

According to this system the line will not test busy after conversation has ceased.

.When the operator gets ready to disconnect she takes down the plugs P, P, and

,their restoration to their seats opens the switches 27 and 28, thereby breaking the circuit through the locking relay F, which lets go, and battery is at once taken off the wire 34, and hence off the relays D and D. These relays then retract, and the cord-circuit is again complete ready for another operation.

The operation according to Fig. 2 is the same-as that of Fig. 1, with the following dif ferences: The relays D and D take current in parallel instead of in series, their windings cl being in separate branches off the wires 16, 17, 34, and when t-herelay F isenergized 35, 23, B. When these relays have pulled up,

dueto the denergization of the relays S and S they lock themselves independently, relay D by the following path: B, S, 21, d (1, 25, 27; and the relay D by the following u it breaks the circuit of the relay F at 38. w he original or operating circuit by way of Wire 35 is then broken and thenceforth each K lows: Assume the call to have originated with subscriber A, in Fig. 1, and the party called for as subscriber -A iii-Fig.8 :Theiop'eration $15 the same asalready:descrrbed-Lup to l the locked.)

testingand insertion of plug Pia: Tlie=wanted subscriber inkthis case beingv in anotheriexchange. the asubscribers operator connects .on an order wire and instructs .t he :trunk operator in Fig. 3=asato thenumher desiredgz-receiving in returnher instructions"touse' 'a particular trunk, say the one shown 1n the figure. The subscriber's operator thenimmediately insertsplug P in thetrunk j ack'J whereupon a circuit (is: closed from i the bate" tery B in Fig.5 1 through the relay .S"an d:the sleeve side of t he trunk, through the winding i'-', relay D wires 55-a1id 56-,winding i to the armature of relay St andegroundr Relay S pulls up as before and puts batteryon the wire RelayD pulls up i-n F iga 3and closes the following circuitforxthe guard lamp X: B,.53, d ,-X, 59; 5S.and ground;

Lamp X lights. and the 'tru'nkjop'era for tests and insertsthe plugPinthe-wanted line ack J. (urrent immediatelyfiows fronr battery B by the following-pathzB,53, 5?;89; 51", 42, d, P", j to relay'Xandzground; 'The cut+otf relay X pulls,up,. and" the relays alsowpulls up, breaking the circuit of lamp X. Then the subscriber-A answers, relay .5 pulls up, being energized by current-flowing .out; to line over the:sleeve: side.i and back over "the tip side. Thisirelay pulls. up, and titsburrent on the lockinglrelavaF bythe ollowing path: B, 48. 47, F,;-19:=50andground; F )ulls up, and" locks itself at the :arhiatureji'.

Ihe pulling upaof relayS* -alsoctakes*tlie.:

ground off of coil .i'andmompletestheametallic circuit therethroIugh,thusperforniingthe same functionfor'the operation of. the supervisory lamp s in F ig. 1 as if the trunkiline were a subscribers linei: TherelayD't'continues to hold upas long;as the 'plug P/isi'n the t-runk-jack-JJ beingt'hen'fbridged across the metallic circuit. T hen the called subscriber hangsnp, the relay 1) imFig. 3 isenergized, and the. lamp X islighted, in the'fol-f;

lowing manner-:11.) Relay Stbecomes de energized,-cutting ofl' the-wire 39 from the coil 5-, and grounding the latter therebycausing the relay S? in Fig. .lto become deaenergized,

whereupon thewires12:and.13 are cut-off as already described. The; cutting- :off fofethese wires deprives the. relay 1) in F-ig*.;*:3. of current, and it lets go, whereupon the relay. D takes current by the :fOllOWlIlg path: B ,.f,

47, 46, (1 43, 11), 45f-and ground. .(It;

will be remembered thatrF. is energized and Relay D? in pulling up', completes the grounded'eircuit: 45; d 42, 51 ,1S 57,3; whereupon the relay S puts current on the lam X through, .the circuit: 13, X, (i 54 and ground. 1r

When the subscribers .hang=-v :up. their. :receivers after conversation, the operationv in .Fig. 1 is the same as; alreadydescribed:,-at least as to thellightingsofrthe laInps. .V-Onp the trunk end, however, the following ensues: relay S lets go, and relay D gets currentby the following path: B, f, 47, 46, d" (D being denergized when S opened the metallic circuit 39), 43, D 45 and ground. Relay D pulling up disconnects the plug P", but puts the ground 45 onto wire 42 so as to keep relay S energized over the following path: B, 53, 57, S 51, 42, d 45 and ground. This maintains lamp X lighted for clearing out, until the plug 1? is withdrawn, and in its seat, when the ground is taken off at 50. relay F lets go, battery is thereby taken off the wire 47, and everything is restored to normal.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a telephone exchange system subscribers lines having switching terminals, operators connective circuits having co-operating switching terminals, and means controlled by the subscribers through said circuits for disconnecting the same for operative purposes from the subscribers lines, without disconnecting or dissociating the said switching terminals, substantially as described.

2. In a telephone exchange system, subscribers lines, having switching terminals, operators cord-circuits having co-operating terminals for" interconnecting the same, switch contacts separated from said terminals normally completing said cord circuits during conversation, electromagnets connected to said circuits and controlled by the subscribers to operate said switch contacts and thereby disconnect all operative parts of the cord-circuit from the subscribers lines at the end of a conversation, substantially as described.

3. 'In a telephone exchange system, sub-.

scribers lines, and operators plug cord-circuits for'interconnecting the same, a cut-off relay for each cord-circuit, and connections therefor such that upon giving a clearing-out signal a subscriber will energize a cut-off relay to sever the cord from his line, without regard to the position of any connecting plug, substantially as described.

4. In atelephone exchange system, a subscribers line and an operators cord-circuit, a clearing out signal connected with said cord and adapted to be controlled by the subscriber to indicate that disconnection is desired, together With a cut-off relay controlling the continuity of the cord at the terminal or subscribers end thereof, and means whereby said cut-off relay is operated upon the operation of the clearing out signal, substantially as described.

5. In a telephone exchange system, subscribers lines and an operators cord-circuit for interconnecting them, a clearing out signal associated with said cord-circuit, and controlled b the subscribers, and a cut-off relay contro ling the continuity of the cord-.

circuit and itself controlled by the operation of the clearing out signal, substantially as described.

6. In a telephone exchange system subscribers lines, with means at the subscribers station for determining the flow of current in each line, a common source of current supply for all the lines, and an operators cordcircuit for interconnecting them, a supervisory signal and a controlling relay therefor associated with the cord-circuit, a cut-off relay also associated with the cord-circuit and controlling the continuity thereof, and circuit connections for said cut-off relay controlled by the supervisory relay, whereby at the conclusion of a conversation and the cessation of the current flow through the subscribers line. the cord-circuit will be severed, substantially as described.

7. In a telephone exchange system, a plurality of subscribers lines and a common source of current supply therefor, an operators cord-circuit having terminal plugs for interconnecting the line jacks, a supervisory relay associated with the cord-circuit and under the control of a subscriber when connected, a cut-off relay controlling the continuity of the cord-circuit, and a locking relay, the circuit of. the cut-off relay being jointly cont-rolled by the supervisory relay and the locking relay, and means whereby said locking relay will operate to place the cut-off relay circuit under exclusive control of the supervisory relay when a connection is completed, substantially as described.

8. In a telephone exchange system, a plurality of subscribers lines terminating in jacks, and an o erators cord-circuit terminating in plugs or interconnecting the lines, a pair of supervisory signal magnets associated with the cord-circuits and so connected that each will respond to the control of one of a pair of connected. subscribers only, a cut-ofl relay controlling the continuity of the cord-circuit, a locking or battery control relay initially controlled by the called subscribers supervisory si nal magnet and a circuit for the cut-off re ay thereby placed under the joint control of both supervisory relays, substantially as described.

9. In a telephone exchange system, sub: scribers lines and an operators cord-circuit having. terminal plugs for interconnecting the lines, a supervisory signal magnetassociated with each. plug and controlled during connection by the corresponding subscriber, a cut-off relay associated with each plug and adapted when operated to disconnect the plug from the cord-circuit, and circuits for a scribers lines and an operators cord-circuit having terminal plugs for interconnecting the lines. a supervisory signal magnet associated with each plug and controlled during connection by the corresponthng subscriber. a cut-off relay associated with each plug and adapted when operated to disconnect the plug-from the cord-circuit. alockmg or hate tery supply relay tuider the control of the calling plug supervisory and adapted to be energized upon the completion of a-connection to supply battery current to the cutotf relay circuits. said circuits being thereafter.

4 jointly controlled by the supervisory signal magnets. substantially as described.

11. In a telephone exchange. system. subscr bers lmes and an operator s cord-circuit having terminal plugs for interconnecting the lines. a supervisory signal magnet associated with each plug'and controlled dtu'ing comiection by the corresponding subscriber. a cut-oil rela associated with each plug and adapted when operated to disconnect the plug from the cord-circuit. a locking or battery supply relay under the control of the calling plug supervisory and ada ited to be energized upon the completion o a connection to supply battery current to the cut-off relay circtuts, said circuits being thereafter jointly controlled by the supervisory signal magnets.- together with means controlled by the operator upon withdrawing the plugs,

to break the cut-off relay circuit and to restore the cord to operative condition. substantially as described.

12. In a telephone exchange system, sub' SCl'ibGlS lines and an operator's cord-circuit ha ing terminal plugs for interconnecting the lines. a supervisory signal ma net associated with each plug and controlled during connection. by the corresponding subscriber; a cut-off relay associated with each plug and adapted when operated to disconnect the plug from the cord-circuit. alocking or battery sup ly relay tmder the control of the calling p ug supervisory and adapted to be energized upon the completion of a connection to supply battery current to the cutoff relay circuits. said circuits thereafter jointly controlled by the supervisory signal magnets, together" with the supplemental winding on eachcut-ofi relay closed to battery through a locking circuit when said relays are excited, and means controlled by the 2 operator in removing the plugs. tobreak said locking circuits and-thereb y restore the cordcircuitto normal conthtton. substantially as described. a

13. In a telephone exchange system. Sub. scnbers hnes and an operator's cord-circtnt ha ing terminal plugs for interconnecting the lines-a supervisory signal magnet as ociated with each plug and controlled during connection by the corresponding subscriber. a cut-ofi relay as ociated with each plug and adapted when operated to disconnect the plug from the cordcircui t', a locking or batcalling plug supervisory and adapted to be energized upon the completion of a connection to supply battery current to the cut-off relay circuits, said circuits being thereafter jointly controlled by the supervisory signal magnets. together with a plug seat switch included in said cutoff relay circuit and opened to restore thesame when the operator withdraws the plugs, substantially as described. 1 x H. In a telephone exchange system. subscribels lines and an operator's cord-circuit having terminal plugs for interconnecting the lines. a supervisory signal magnet associated witheach plug and controlled during connection by the corresponding subscriber. a cut-ofl' relay associated with each plug and adapted when operated to disconnect the plug from the cord-circuit. a locking or bate tery supply relay antler the control of the calling plug supervisory and adapted to be energized upon the completion of a connection to supply battery current to the cut-off relay circtuts. said circuits being thereafter jointly controlled by the supervisorv signal magnets, together with a plug seat switch a:- sociated with each plug. and controlling the cut-ofi relay circuits, substantially as described.

15." In a telephone exchange system. subscribers' lines and an operators cord-circuit having terminal plugs for interconnecting the lines. a supervisory signal magnet associated with each plug and controlled during connection by the corresponding subscriber. a cutoff relay associated with each plug and adapted when operated to disconnect the plug from the cord-circuit. a locking or bat tery supply relay under the control of the callingiplug supervisory and adapted to be energized upon tue completion of a connection to supply battery current to the cut.

off relay circuits. said circuits being thereafter jointly controlled by the supervisory signal magnets. together with a pair of plug seat switches controlling parallel branches to complete said cut-ofi relay circuit. whereby both plugs must be withdrawn and in their seats in order to restore the circuits. substantially as described.

16. In a telephone exchange system. subscribers lines. means under the control of operators for interconnecting the hues. and means controlled by the subscribers independently of tne operators for severing in two parts the operators connecting means. substantially as described.

k In testimon whereof I afiix my signature in presence of two witnes es. wnium w. DEAN.

.Witneme i p A. D. P. LIBBY,

Snjxnr A. BEYLAND.

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